Compressor-motor apparatus



June 24, 1947.

A. LATHAM. JR

COIPRES SOR -MOTOR APPARATUS 7 Sheets-Sheet 1 Filed June 20, 1944EZENTORU TTORNEYZ June 24, 1947. A. LATHAM, JR

COMPRESSOR-MOTOR APPARATUS Filed June 20, 1944 '7 Sheets-Sheet 2 Je 4,1947 A. LATHAM. JR

COMPRESSOR-MOTOR APPARATUS Filed June 20, 1944 7 Sheets-Sheet 3 INVENTORmwmm au BY ATTORNEYS June 24, 1947. A. LATHAM; JR 2,422,789

COMPRESSOR-MOTOR APPARATUS Filed June 20, 1944 7 Sheets-Sheet 4 ATTORNEm? @E. Q m zkwqigli/ -f F M na J... h Q Q m .HFHHLI W W. J

June 24, 1947. LATHAM' JR 2,422,789

COMPRES SOB-MOTOR APPARATUS Filed June 20, 1944 '7 Sheets-Sheet 5 June24, 1947. A. LATHAM. JR

I COMPRESSOR-MOTOR APPARATUS Filed June 20, 1944 7 She ets-Sheet 6INVENTOR ;Y X ATTORZEYS Patented June 24, 1947' COMPRESSOR-MOTORAPPARATUS Allen Latham, Jr., Jamaica Plain, Mass, assignor to Arthur D.Little, Inc., Cambridge, Mass., a

corporation of Massachusetts v Application June 20, 1944, Serial No.541,159

This invention relates to compressor-motor apparatus. It relatesespecially to compressor-motor apparatus of the rotary reciprocatingpiston type. r

It is a general object of this invention-to provide compressor-motorapparatus for compressing a gaseous material as a result of mechanicalpower supplied to the apparatus or for taking oil mechanical power byexpansion of a gaseous material supplied to the apparatus. It is a,further object oi. this invention to provide compressormotor apparatushaving high eiliciency and high capacity for its size and weight. It isa further object, according to preferred embodiments of this inventionto provide compressor-motor apparatus which is operable notwithstandingabsence of 111-- bricant in the region of the apparatus wherein thegaseous material comes in contact with the I ly desirable for affordinga supply 01 compressed air for any purposes such as operation of one ormore compressed air motors. The apparatus is also suitable forcompressing a'vapor such as steam or for converting the energy ofcompressed;

steam into power. When reference is made herein to gaseous material, itis to be understood that 28 Claims. (Cl. 230185) tered. On the otherhand, expansion engines for handling combustion gases and the likeoperate at very high temperatures under which no existing lubricantshave been found to besatisfactory. Another advantage of thecompressor-motor apparatus of this invention is that it hasmechanically-actuated admission and discharge valves. Therefore, nopressure is required for opening these valves and favorable conditionsare provided for compression or expansion of gaseous material which isat or near its saturation temperature such as has to be handled incertain invention is operable, thereby providing large cathe referenceis to either gases or vapors or mixtures of gases and vapors, thegaseous material being compressible.

The compressor-motor apparatus 101' this invention is of advantage inthat it not onlyhas application for uses to which ordinary reciprocatingcompressor-motors are put, but also under unusual, special and diilicultconditions. One of such special conditions is the supply of gaseousmaterial which is not contaminated with lubricant, and the apparatus oi!this invention is especially advantageous for such purpose. Thecompressor-motor apparatus of this invention is likewise of greatadvantage for operation under conditions which involve extremes oftemperature at which no known lubricant will function satisfactorily.Expansion engines used for gas liquefaction must operate withoutlubricant because of the extremely low temperaturesencounpacity relativeto the size of the unit, is also of great advantage in the handlingofvapors that are at or near their saturation temperature.

It is a further advantage of the compressormotor apparatus of thisinvention that it can readily be produced with very small clearancevolume in the'compression-expansion space, thus making it adaptable tohighly eflicient operation.

The compressor-motor apparatus of this invention can likewise beproduced with an unusually high ratio of-port area to pistondisplacement, which is of advantage in affording 'a device that isoperable at unusually high speeds. A further advantage that is incidentto the high speed operation of the device of this'invention resides inthe fact that the compressor-motor apparatus can be made of unusuallylow weight and bulk as compared with conventional reciprocatingcompressors and motors. Moreover, problems of impaired efliciency due toleakage of gaseous materialbeing handled, are reduced because of smallerdimensions of the regions where scaling is tobe effected. I

Notwithstanding the utility of the compressormotor apparatus of thisinvention under special 'and exacting conditions, it is of furtheradvantage that the apparatus is practical and economical both toconstruct and to maintain. Thus the surfaces which must operate withclose clearances are either cylindrical or flat and therefore There area number of features of this inven-.

tion which are preferably availed of in combination but which may beavailed of separately in The high speed at 3 compressor-motor apparatusof this invention- Before describing the specific embodiments of thisinvention which are shown in the drawings and described hereinbelow,brief reference will be made to some of the features of this invention.

Certain of the features of this invention relate to the combination of arotary and reciprocatory rod with a coaxial peripherally cylindricalpiston and with bearing means for the rod which fixedly maintains theaxial alignment of the rod and of the piston so that the piston may beoperated out of pressure-contact with the cylinder in which it operates,thereby avoiding necessity for lubrication between the piston and thecylinder. Th combination of the piston-carryin rod with a power shaft inaxial alignment therewith and with an axially slidable means fortransmitting rotational power between the shaft and the rod is a furtherfeature of the invention that is of importance in effecting asmoothly-operating continuous rotation of the parts and reciprocation ofthe piston, especially for high speed operation.

librium of the forces acting on the piston by the gaseous material beinghandled.

Further features of this invention relate to means interposed betweenthe piston and the reciprocating means for preventing lubricant for thereciprocating means reaching the compression-expansion chamber. Inpreferred embodiments, spaced bearings for the rotating andreciprocating rod are interposed between the reciprocating means withtrap means for the lubricant between these spaced bearing means.Preferably, also, there is a lubricant flinging means carried by the rodthat throws lubricant into the trap means. Moreover, in preferredembodiments, one or more bearing means between the reciprocating meansand the compression-expansion chamber is mounted on a support whichprojects inwardly into a housing or chamber so that the device can beoperated in any position without having a bath of lubricant contactingsuch bearing means. Likewise, in preferred embodiments, the inwardlyprojecting bearing support is surrounded by an inwardly projectingshield or sleeve spaced therefrom and a vent for the space between theshield and the bearing support is provided. The trap means can likewisebe connected with the high pressure side of the compressor-motor toprevent seepage of lubricant into the trap means.

Another feature of this invention resides in the provision of anessentially gasproof casing about the reciprocating means and associatedmotor or-generator operatively connected to the reciprocating androtatable rod which entraps any gaseous material that may seep past abearing between the compression-expansion chamber and the reciprocatingmeans so as to build up a back pressure that minimizes such tendency ofgaseous material to escape from the compressionexpansion chamber.

Further features of this invention relate to the porting means employedin connection with the expansion-compression chamber and the provisionof such porting by means of valve ports in the piston or piston'slrirtfor cooperation with inlet and outlet ports of the cylinder in which thepiston operates. One such porting arrangement in preferred embodimentsincludes the provision of diametrically-opposed simple openings in thepiston periphery or skirt as valve port means and the provision of pairsof diametrically-opposed simple openings in the cylinder wall which arelocated for being traversed by the valve port means in the piston skirtso as to control inlet and outletof gaseous material. This constructionmay advantageously be used so as to provide inlet and outlet ports forthe cylinder which are common to compression-expansion chambers onopposite sides of an intermediate barrier or head of a double-actingpiston. In such construction utilizing a double-acting piston, it isalso a feature of this invention that the barrier or head between theoppositely-extending piston skirts is substantially thinner than the hubfor aflixing the piston to the rod.

Another feature of this invention relates to the movability of thenormally-stationary cylinder in which the piston reciprocates forreversing the operation of the device. Other features relate to theprovision of a plurality of piston means afiixed in coaxial relationwith the rotating and reciprocating rod and effecting operativecommunication between the compression-expansion chambers associated withthe pistons. Other features of this invention relate to the provision offirst and second reciprocating and rotating rods in 'axial alignmentwith each other'and causwith the following typical embodiments of thisinvention which, for illustrative purposes, are described below andshown inthe accompanying;

drawings, wherein Figure 1 is a side elevation, partly in section,

of compressor-motor apparatus according to this invention;

Fig. 1A is a side elevation, partly in section,

, showing the detail of the other end of the device of Fig. 1;

Fig. 2 is a section taken on' the line 22 of Fig. 1, showing the exhaustports open;

Fig. 3 is a section taken on the line 3-3 of Fig.

Fig. 4 is a section taken on the line 4-4 of Fig. 1;

Fig. 5 is a side elevation of the end of the rotatable andreciprocatable rod and the small piston located at the end of such rod:

Fig. 6 is an end sectional elevation similar to Fig. 2 but showing analternative cylinder construction that is adapted for rotation toreverse the action of the device;

Fig. 'l is a fragmentary side sectional elevation taken on the line |-'Iof Fig. 6;

Fig. 8 is an end elevation of the cam member of the reciprocating meansof the device;

Fig. 9 is a horizontal section taken on the line 9--8 of Fig. 8;

Fig. 10 is a vertical section taken on the line lD-ill of Fig. 8;

Fig. 11 is a side elevation of the large piston 15 member of thedeviceshown in Fig. 1;

Fig. 12 is a left elevation of the piston member shown in Fig. 11;

Fig. 13 is a right elevation of the piston member shown in Fig. 11; v

Fig, 14 is a developed showing of the travel of a port valve of thepiston past the intake port in the cylinder of the device shown in Fig.1;

Fig. 15' is a developed showing of the travel of a port valve of thepiston past the exhaust port in the cylinder of the device shown in Fig.1;

Fig. 16 is a sectional elevation of an alternative porting arrangementbetween the valve ports in the piston and inlet and outlet ports of thecylinder; 5

Fig. 17 is a top plan view of the cylinder shown in Fig. 16;

Fig. 18 is a top plan view of the piston shown in Fig. 16;

Fig. 19 is a side sectional elevation of an alternative piston andporting arrangement that may be employed in the practice of thisinvention;

Fig. 20 is a section taken on the line 20-20 of Fig. 19.;

Fig. 21 is a sectional elevation of an alternative power transfer devicefor rotating a rotatable and reciprocatable rod;

Fig. 22 is a schematic view of a typical installation ofcompressor-motor apparatus according to this invention; and

Fig. 23 is a schematic view of another typical of the piston head orbarrier 43 are the openended skirts 44 and 45. In the skirt 44 arediametrically-opposed valve ports 46. The skirt 45 is provided withdiametrically-opposed valve ports 41 which are at a 90 angle withrespect to the valve ports 46' The end of the cylinder 3| is providedwith a cylinder head 48 which is fixed to the cylinder 3| as by bolts49. The cylinder head 48 is provided with a member 50 which is reentrantinto the compression-expansion space within the cylinder 3|, which fitswithin the open-ended skirt and over the hub 4| of the piston and whichsubstantially completely fills the space within the skirt 44 between itand the reentrant hub member 4|. This is clearly shown in Fig. 1 whereinthe rod 38 and the piston 40 are moved to the installation ofcompressor-motor apparatus according to this invention;

A typical embodiment'of compressor-motor apparatus according to thisinvention is shown in Figs. 1 to and 8 to and comprises a main housing35 which has the cylinder 5| extending therefrom and integral therewith.The cylinder 3| may advantageously have the fins "protruding therefromso as to provide extended surface area for the dissipation of heat. Withreference to the cylinder 3|, the word cylinder is used as applicable toany member having a cylindrical inner surface adapted for thereciprocation'of a peripherally cylindrical piston therein, withoutregard. to the shape of theextemal surface and whether the externalsurface is cylindrical or is of some other shape, such as a squareshape, as shown in H8. 2. Within the cylinder there is fitted a cylinderhead ll which is reentrant into the compression-expansion space withinthe cylinder 3|. The cylinder head 33 has a bearing support 44 integraltherewith that supports the bearing 35 for the rod 38. The term"cylinder head is used herein whether or not a rod or the. like does, ordoes not, pass therethrough. Projecting from, and inwardly into, thehousing 35 is another'bearing support 35 which supports the bearing 31.The rod is maintained in fixed axial alignment by the bearings and 31which afford continuous rotary motion and reciprocatory motion for therod 35. The rod 28 may be either solid or hollow and in the embodimentshown the rod 35 is in the form of a hollow tube.- Ordinarily, it ispreferable to use a hollow rod, inasmuch as the weight of thereciprocating parts of the device thereby may be diminished withoutundue sacrifice of strength.

Rigidly fixed to the rod 35 for rotation and reciprocationtherewith isthe piston which is indicated generally in Fig. 1 by the referencecharacter '40 and which is shown in detail in Figs, 11, 12 and 13. Thepiston 40 comprises a hub member 4| which is reentrant into thecompression-expansion chamber within the cylinder. A suitable pin 42 orthe like may be,provided for rigidly extreme right osition. In a similarway, the cylinder head 3 fits within the piston skirt 45 andsubstantially completely fills the space within thepiston skirt 45 whenthe rod 38 and piston 40 are moved to the extreme left position.

In connection with the apparatus as described thus far, itis to be notedthat the rod 38 is maintained in fixed axial alignment by the bearings35 and 31 and that the rod 38 acts as a guide for the piston so that thepiston does not bear against the inner wall of the cylinder 3|. It ispreferred to machine the peripherally cylindrical surface of the piston40 so that it will be maintained in proximity to the inner wall of thecylinder 3| with very close clearance but essentially out-ofcontacttherewith. It is not essential, however,

that the piston 40 be completely out-of-contact with the, inner wall ofthe cylinder 3| and there may be some contact between the periphery ofthe piston and the inner wall of the cylinder. However, since the rod 38acts as a guide for the piston, there is no force'which causes thepiston to bear against the inner walliof the cylinder. Such mounting ofthe piston is referred to herein as being a mounting which maintains theperiphery of the piston out of pressure-contact with the inner wall ofthe cylinder. When the periphery of the piston is out ofpressure-contact with the inner wall of the cylinder, any minorconcording to the structure above described, to rotate and reciprocatethe piston 40 within the compression-expansion space provided by thecylinder 3| without the use of any lubricant. Moreover, no piston-ringsor the like are required. This, as aforesaid, is of great advantage forcertain applications of the compressor-motor apparatus of thisinvention.

In order to properly control the intake and ex burst from thecompression-expansion chamber within thecylinder II, the cylinder 3| isprovided with intake and exhaust ports. embodiment shown in Figs. 1 and2, the intake ports 5| are in the form of simple openings of substantialsize, the openings being disposed as a pair, one being diametricallyopposedto the other. The exhaust ports 52 are also arranged in a pair,one being diametrically opposed to the other. The intake and exhaustports are in the form of what is referred to herein as simple open ings,namely, openings which are either round or fixing the hub 4| tothe rod35. On each side. square or other simple shape but which do not In thehave any special configuration for following the travel of the portvalves and 41 during the reciprocatory and rotary'movement of the pistonwithin the cylinder. The valve ports 46 and 41 in the piston skirts arereferred to herein as the valve means for the purpose of clarity in thedescription and in the claims and to distinguish from the inlet andoutlet ports in the cylinder, although the valving action broadlyconsidered is accomplished by these valve ports in conjunction with theopenings in the cylinder which provide the inlets and outlets.

In Fig. 14, the'travel of one of the valve ports 48 past one of theintake ports is shown by indicating one of the valve ports 46 in aplurality of different positions relative to the intake port II. Thefull dimensions of one oi. the valve ports '46 is shown in solid lines.In position (a), shown in dotted lines, the valve port 46 is juststarting to traverse the intake port ii. In position (b), the valve port46 has been advanced on the intake stroke of the piston and is morefully opened for drawing gaseous material into the compression-expansionchamber. In position (0), the valve port 46 is nearly Completelyuncovered and a large part of it is available for the intake of gaseousmaterial in thecompression-expansion space. When the port valve 46 is inthe position shown in solid lines, the intake stroke of the.

piston has been nearly completed. In position (d) the port valve 46 isabout to leave the intake port 6|, thus sealing the gaseous material inthe interior of the compression-expansion chamber.

Referring to Fig. 15, there is indicated the travel of one of the valveports 46 past' the discharge or exhaust port 52. Since the device ofthis invention is operable either as a compressor or as a motor the termdischarge, which is more common in connection with compressors, is usedsynonymously with the term exhaust, which'is more common in connectionwith motors. and both are used synonymously with "outlet." The outletport is smaller than the intake port and usually is so positioned thatin compression the pressure in the compression-expansion chamber will beraised substantially due to the discharge stroke of the piston beforethe outlet port is opened. By suitable design, the compressor-motorapparatus can be made so as to build up any predetermined desireddischarge pressure before the outlet port is opened. It is usuallypreferable to build up the desired predetermined pressure within thecompression-expansion chamber so that it will be substantially the sameas the pressure maintained at the outlet port before the outlet port isopened. When the valve port 46 is in the position shown in solid linesin Fig. 15", the outlet port 52 has just become opened. As the pistoncontinues to move to the right on the discharge stroke of the pistonwhile revolving, the port valve 46. will occupy the positions (e) and(I) which are shown in dotted lines before,the travel of the valve port46 past the outlet port 52 has been completed.

The travel of the port valve 41 past the inlet and outlet ports isessentially the same as that described in connection with Figs. 14 and.15 but in the opposite direction. It is to be noted that 38 than thevalve ports in the piston skirt, this construction contributing to therapidity with which the compression-expansion pace may be filled and tothe reduction of the clearance volume between the piston and thecylinder heads. It is preferable that the piston skirt be provided withdiametrically-opposed valve ports and that one pair of inlet ports andone pair of outlet be noted that the inlet ports havesubstantiallygreater angular extent about the axis of the rod the inlet and outletports in the cylinder be arranged in the form of pairs ofdiametricallyopposed openings. In this way, the radial analysis offorces due to incoming and outgoing gaseous material may be reducedsubstantially to zero about the axis of the rod 38. a I

The rod 38 is actuated by means of a power shaft 53 which may be thepower shaft of an electric motor. The end of the power shaft 53 isprovided with a spline stub 54 which is slidable telescopically withinthe spline connection 55 at the end of the rod 88. In this manner, thepower shaft 53 is rotatable and will cause the rod 88 to rotate whilepermitting the rod 38 to reciprocate. Similarly, a reciprocatoryandrotary motion of the rod 38 will cause thepower shaft 68 to rotate whenthe device is being used as a motor.

Fixed to the rod 88 is the cam member which is indicated generally bythe reference character 56 and which is provided with an undulatoryannular ring 51 which has on each side thereof complementary cam track58 and 58 (see Figs. 8, 9 and 16) Carried by the interior of the housing30 are fixed cam guide means in the form of guide rollers 59. There isone pair of guide rollers 59 with each roller directly opposite theother on each side of the cam ring 51 and another similar {sir of amrollers 59a that is diametrically opposed to e pair of rollers 59. Inthis manner, the forces acting on the cam member are axially balancedwith reference to the axis of the rod 38. If desired, more than twopairs of cam rollers may be used when the cam is designed to providemore than, two reciprocations of the piston per revolution, but in anycase it is preferable, according to this invention, to have the camrollers disposed so that their action on the cam" will be axiallybalanced with reference to the axisof the rod 38. Thus the forces actingon the cam are in alignment with the axis of the rod and there isvirtually no thrust of the rod against either of the bearings 35 and 31.

It is to be noted that there is a small chamber 60 between the bearings35 and 31 which acts 'as a trap for any lubricant which may pass thebearing 31 from the housing 30 for the cam, the cam guide rollers andthe spline connection with the power shaft. The parts just mentionedwhich are within the housing 30 are preferably operated to prevent suchlubricating oil from reaching the parts of the device that are incontact with the gaseous material being handled, and, by the provisionof the trap chamber 60, any such lubricant is trapped before it canreach the bearing 85. It is preferable, in order to prevent anylubricant from traveling along the rod 38, to afilx to the rod 2,lubricant-flinging member 6| which effectively prevents lubricantfromtraveling along the rod beyond this lubricant-flinging member. If

desired, the lubricant trap'60 may be provided with a drain 62 so thatany lubricant collected in the trap 60 can be drained off through thedrain 62 and line 63, valves I55 and I56 being open and valve I57 inline I58 being closed. However, the amount of lubricant that iscollected in the trap 50 is very slight and, if desired for certainapplications of the'device, the drain 52 may be omitted or valve I55closed. By providing a drain 52 open to the atmosphere, the pressure inthe lubricant trap 80 is maintained at atmospheric pressure which isnormally less than the pressure of the aseous material in thecompression-expansion space within the cylinder 3i. This pressuredifferentlal thus maintained acts as a further preventative for anyseepage of lubricant past the bearing 35 in the direction of thecompressionexpansion space.

When, on the other hand, the drain 52 is omittea or the valve I55 isclosed, there is a tendency for gaseous material to seep past thebearing 35 from the compression space within the cylinder 3I so as toprevent seepage of lubricant toward the compression space from the trap50 and so as to build up pressure in the trap 60, which pressure, inturn, urges any lubricant tending to seep past bearing 31 from the camhousing back into the cam housing especially when the cam housing isvented to the surrounding atmosphere or is otherwise maintained under apressure that is.

lower than the pressure maintained in the trap 50. If desired, thepressure in trap 60 can be positively maintained as by closing valve I56and opening valves I55 and I51. the valve I51 being in line I58 whichleads to the high pressure side of the compressor-motor, e. g., to thedischarge line when the device is used as a compressor (se Fig. 22).

It is a further feature of the construction shown, that the support 35for the bearing 31 projects a substantial distance into the housing 30.Such construction prevents the bearing 31 from being operated in contactwith a bath of lubricant regardless of the position in which thecompressor-motor apparatus is disposed. Similarly, the cylinder head 33is provided with the reentrant support 34 for the bearing 35 so as toprevent any lubricant entrapped in the lubricant trap 60 from reachingthe bearing 35 regardless of the position in which the compressor-motorapparatus is used. Preferably the bearing support 36 is surrounded by asleeve or shield member II which is of circular cross section and whichis spaced from the support 35. The space between the bearing support 36and the sleeve I5! is provided with a vent I52 so that the housing forthe cam member may be maintained at a pressure lower than the pressuremaintained in the trap 60 for the purpose explained hereinabove, theplug I53 for the vent I52 in such case being removed. The purpose of thesleeve I5I is to prevent any lubricant from escaping through the ventI52 when the device is up-ended (the right end being at the bottom) andfor this reason the right hand end of the sleeve is secured tightly tothe main housing 30 so that no lubricant will flow by it out of thetrough I54 where lubricant will collect if the device is thus up-ended.

For certain applications of the compressormotor apparatus of thisinvention, it is desirable to build up pressure in the region of thepowertransfer mechanism, including the spline connection and the cammechanism, so as to minimize any tendency of gaseous material to seeppast the bearing 35 from the compression-expansion space toward thepower transfer mechanism. In such case, the drain 62 for the lubricanttrap 50 is either omitted or the valve I55 is closed and the vent I52 isomitted or provided with a suitable plug I53. The power-transfermechanisms are also provided with an over-all casing 64 which be, ofwhich the power shaft 53 is a part. The

casing 64 is secured to the housing 30 as by bolts 55, and packingmaterial 66 is provided'so that there is an essentially gas-proof casingmeans about the mechanisms with which the rod 38 is operativelyconnected. By such construction, if there is a. gradual'seepage ofgaseous material from the compression-expansion space within thecylinder 3|, past the bearing 35 and past the bearing 31, such gaseousmaterial will gradually build up a back pressure, with the result that,when the back pressure has been increased sufllciently, the tendency forfurther seepage of gaseous material past the bearings 35 and 31 will becounterbalanced.

It is a further advantage and feature of this invention that a pluralityof piston members can be carried on a single rod that is arranged forrotation and reciprocation. A simple form of secondary piston isillustrated in the drawings. In the device shown in Figs. 1, 3, 4 and 5,the rod 38 is hollow and a secondary piston may be readily provided byrecessing a. substantial distance from the end thereof a piston head 81which is rigidly carried on the interior of therod 38 which protrudesbeyond the piston head 61 as a piston skirt 68. The head 48 for the maincylinder 35 has integral therewith a secondary cylinder 59 in which thepiston skirt 68 reciprocates. The end of the cylinder 59 is providedwith a head 10 which has a reentrant member N that fits into theopen-ended. piston skirt 68. The cylinder 69 is provided with a pair ofdiametrically-opposed inlet ports 12 and with a pair ofdiametrically-opposed outlet ports 13. The piston skirt 68 is providedwith a pair of diametrically-opposed valve ports 14. The intake andexhaust are controlled by the inlet ports 12 and the outlet ports 13 andby the valve ports 14 in the same manner as has been describedhereinabove in connection with the larger or main piston and surroundingcylinder.

In Figs. 6 and 7, optionally-employed means are shown for reversing theaction of the compressor-motor. The rotatable and reciprocable rod 38,the piston 45, and the cylinder heads 33 and 48 are the same asdescribed above in connection with Figs. '1, 2, 11, 12 and 13. Thecylinder 3| is also the same except that it is cylindrical exteriorlyaswell as interiorly and except that it comprises a port sleeve 12'which provides part of the cylinder that surrounds the piston. The portsleeve is provided with a pair of diametrically-opposed inletports 13 towhich the inlet lines 14 are secured. The port sleeve 12' is likewiseprovided with a pair of diametrically-opposed outlets 15 to which theoutlet lines 15 are secured. These inlet and outlet ports and linesco-operate with the valve ports in the piston skirt in the mannerhereinabove described. In the construction shown in Figs. 6 and 7,however, the port sleeve is rotatable about the axis of the rod 38 sothat the relative angular position between the cam and cam guide means,on the one hand, and'the inlet and outlet ports in the port sleeve, onthe other hand, can be changed. By turning the port sleeve 12' about andadjusting it to desired position, it is apparent that the inlet portwill be where the exhaust port formerly was and that the exhaust portwill be where the inlet port formerly was. Therefore, what was formerlythe exhaust line becomes the inlet line and. what was formerly the inletline becomes the 11 exhaust line. If the device is being used as acompressor, the direction of action of the compressor will be reversed.If the device is being used as a motor with the gaseous material underpressure being forced in through the same line at all times, thedirection of rotation of the rod 38 will be reversed.

In Figs. 1 to 15, the preferred arrangement of valve-controlled inletand outlet means for the compression-expansion chamber has beendescribed. Such porting arrangement i preferred, not only because itprovides both hydraulic and dynamic balanceof the action of the gaseousmaterial on the piston and relative to the axis of the rod, but alsobecause it enables the port areas to be of large size and permits smallclearance volume between the piston and the cylinder heads. By thearrangement shown, the clearance volume can thus be reduced virtually tothe capacity of the valve ports in the piston. Since these valve portsare in the form of simple openings that extend directly through thepiston skirt, the clearance volume is very low. By utilizing only asingle port valve in the piston, the clearance volume can be reduced toan extremely low value, but by so doing the hydraulic balance of theforces of the gaseous material acting on the piston is sacrificed. Asdistinguished from simple ports in the piston skirt which extenddirectly through the piston skirt, elongated ports or channels in thepiston, if used, tend to increase considerably the size of the valveport means that communicates between the compression-expansion chamberand the inlet and exhaust ports which in turn increases considerably theclearance volume and reduces the efl'iciency of the apparatus. Inaddition, the preferred arrangement of valve-controlled inlet and outletport means permits the employment of ports and valves of high flowcapacity so that the filling and emptying of the piston is very rapid,thereby permitting high speed operation.

While a preferred arrangement of valve-controlled inlet and outlet portshas been described above, other porting arrangements may be employed inconnection with compressior-motor ap- Daratus embodying this invention.One such alternative porting arrangement is shown in Figs. 16, 17 and18. The rod 38 shown in these figures may, for example, be rotated andreciprocated in the manner that has been described hereinabove andcarries, in fixed relation thereto, the piston which is indicatedgenerally by the reference character I83. The piston I83 has a centralhead I8 from which a hub 19 protrudes for establishing firm union withthe rod 38. From each side of the head 18,-the open-ended piston skirts88 and 8! extend. These piston skirts are peripherally cylindrical andare coaxial with the rod 88 and are surrounded :by the cylinder 82. Thecylinder 82 is provided with a head 88 having a reentrant member 84 thatis adapted to fit within the skirt 88. At the other end, it has 9. head86 having a reentrant member 88 that is adapted to fit within the skirt8| and likewise is adapted to fit over the hub 19. The cylinder isprovided with the inlet ports 81 and 81 and opposite thereto with outletports 88 and 88. The line of travel of the inlet ports 81 and 81' alongthe periphery of the cylinder skirts traverses the openings 89 and 89which are on diametrically-opposite sides of the piston skirts. Theoutlet ports 88 and 88' do not follow the same line of travel along thepiston wall and do not traverse the valve port openings 89 and 89' butdo traverse the valve port openings 98 and 98' which are disposed indiametrically-opposed pairs.

While the porting arrangement shown in Figs. 16, 1'7 and 18 is suitable,it may be noted that the valve port openings 89, 89' and 98, 98' are notsimple openings but are elongated and are curved slightly to follow theinclination of the cam track of the cam means for reciprocating thepiston. Since these openings are considerably larger than is necessaryto provide a port of similar flow capacity using the embodiment of thisinvention shown in Figs. 1 to 15, the resulting clearance volume iscorrespondingly greater. Moreover, it is usually desirable, in order toafford more free flow of gaseous material to and from thecompressionexpansion chambers, to provide the recesses 8I and 93 in thereentrant member 84 of cylinder head 83 adjacent the exhaust port 88 andthe inlet port 81 respectively, and corresponding recesses 92 and 94 inthe reentrant member 88 of cylinder head 85 adjacent the exhaust port88' and the inlet port 81' respectively. Such recesses further increasethe clearance volume of the compression-expansion chambers.

When very low clearance volume is not essential, one can, in thepractice of this invention, dispense with the skirted pistonconstructionv and can employ a simple peripherally cylindrical pistonhaving valve ports in the side wall thereof. Such an alternativeembodiment of this invention is shown in Figs. 19 and 20. The rotatableand reciprocatable rod 38 may be as described hereinabove. Secured tothe end of the rod 38 is the solid piston 95 which has diagonaldrillings 96, 96' taken from one end thereof and which provide simplevalve ports in the side wall of the piston that are diametricallyopposite. On the other side of the piston are similar drillings 91, 9'!located at a 90 angle with respect to the drillings 88, 98'. Surroundingpiston 85 is the cylinder 98 which is provided with cylinder heads 99and I88. The cylinder 98 has a pair of diametricallyopposed inlet portsI8I and a pair of diametrically-opposed outlet ports I82. These inletports and outlet ports correspond with the inlet ports BI and 52 in theembodiment of this invention shown in Figs. 1 to 15 and are traversed bythe valve ports provided by the drillings 98, 96 and 91, 91 in themanner that has been described hereinabove in connection with Figs. 1 to15. However, it is apparent that the drillings 98, 98 and 91, 91'increase the clearance volume in their respective compression-expansionchambers. The construction shown in Figs. 19 and 20 is also lessdesirable, especially for high speed operation, since a solid pistonweighs considerably more than a skirted piston of the characterhereinabove described. By use of a skirted piston and by the employmentof a thin piston head in combination wltha hub of substantially greaterextent along the axis of the rod than the piston head, a sturdyconstruction is provided and at the same time the reciprocating partscan be made of very light weight, which is advantageous.

An alternative power-transfer means for providing an axially slidableconnection between the rotatable and reciprocatable rod and therotatable power shaft in axial alignment therewith is shown in Fig. 21.The rotatable and reciprocatable rod 38 may be according to any of thepreceding embodiments of this invention. The rod 38 carries a cam memberI which may be generally similar to the cam member shown in Figs. 1, 9,10 and 11 and which cooperates with appropriate guide Fixed to the endof the the rod 88, is the cross bar I81 which has drive pins I08, I08that project therefrom parallel to the rod 38 and that fittelescopically into the holes I09, I through the cross bar IIO of thecam member I05. If desired, a guide pin III, which is coaxial with theshaft I and the rod 38 and which fits telescopically within the hole IIIthat is also axially aligned, may be employed to assist in maintainingthe shaft and rod in axial alignment. With the construction shown, thepower shaft I06 will rotate with the rod 38 while permittingreciprocation of the rod 38. Powertransfer means such as that shown inFig. 21 is particularly useful under heavy load conditions.

In Fig. -1 of the drawings, only one end of compressor-motor apparatusis shown in detail. The opposite or left hand end of the device is shownin detail in Fig. 1A and is shown diagrammatically in Figs. 22 and 23.In Fig. 1A the parts of the mechanism have, for purposes of brevity,been indicated by the same reference characters as the parts shown inFig. 1- except that a prime is associated with each of the referencecharacters shown in Fig. 1A. In the device shown, the parts shown indetail to the right of the power shaft 53 are shown repeated in allrespects to the left of the opposite end of the power shaft 53 exceptthat the cam means for reciprocating the rod 38' is arranged to effectmotionthat is complementary to the motion of the rod 30. In other words,both rods, which are in axial alignment with the power shaft, arerotated at the same speed as the power shaft and both rods moveoutwardly simultaneously and at the same rate and to the same extent andthen move inwardly simultaneously and at the same rate and to the sameextent, the rods being of the same weight and carrying parts of the sameweight. In this manner, the inertia forces of the reciprocating rods andof the reciprocating pistons, which are identical, counteract andminimize vibration. While the moving parts at opposite ends of thedevice can be arranged in this way so that the inertia forces of themoving parts at one end of the power shaft complement or substantiallycounteract the inertia forces of the moving parts at the opposite end ofthe power shaft, this can be accomplished in other ways since theinertia forces exerted by the moving parts, for any fixed rotationalspeed, are a function of the length of the piston stroke and the weightof the moving parts. .It is apparent, therefore, that the weight of themoving parts and the stroke of such parts at opposite ends of the powershaft can be adjusted so that while the weight and stroke mayindividually be different, the inertia forces of the parts at theopposite ends of the power shaft will be the same or will substantiallycounteract each other and thereby minimize vibration. In addition tocounteracting the inertia of the moving parts, the intake and dischargeoccur simultaneously and the forces due to the gaseous material handledby the cominvention may be made of any suitable size.

under pressure, such as steam, hot combustion gases, or the like, isintroduced into the compression-expansion chambers associated with'thepistons. However, in such case the inlet means for the gaseous materialunder pressure in such case is the same as the outlet means for gaseousmaterial when the device is used as a compressor. Upon the introductionof the gaseous material under pressure, the expansion of the gaseousmaterial causes the pistons to reciprocate and the reciprocation of thepistons causes the rod 38 to rotate as it reciproc-ates, the rotarymotion of the rod 38 being transferred to the power shaft 53. In suchcase, the motor generator II3 may act as a generator for electric power,the electric power being taken off through the lines Ill and II5. Sincethe power shaft 53 may be connected either with a motor or with agenerator, depending upon whether the device is used as a compressor oras a motor, the term motor-generator" is used broadly herein and in theclaims as referring to a device which may act as a motor but not as agenerator, or which may act as a generator but not as a motor, or whichmay act either as a generator or a motor. In the ordinary ease, themotor-generator is electrical, but this is not essential and the powershaft 53 may be comprised in any device which is adapted to supply powerto the shaft 53 or which is adapted to be driven by the shaft 53. Whenthe apparatus of this invention is used as a motor, it is usuallydesirable to employ some inertia wheel or the like which can, forexample, be carried by the power shaft. In th device shown, the rotatingparts of an electric generator will act suitably as-an inertia wheel.

Compressor-motor apparatus embodying this It is an advantage of thisinvention that the com- 'pressor-motor apparatus may be made ofrelatively small size and of a very compact character. Compressor-motorapparatus of this invention may be made small and compact so as to becapable of supplying from about one-half to fifteen cubic feet of airper minute compressed from atmospheric pressure to about five to twentypounds per square inch. In a small-sized unit of this character, theunit can be operated at relatively high speed, such as 1700 to 3450 R.P. M. Even considerably higher speeds are also possible. The device canbe made in larger sizes and can readily handle a thousand or more cubicfeet per minute. When the device is made so as to be of large capacity,the rate of operation is ordinarily somewhat lower than mentioned above,due to the greater inertia of the moving parts. While thecompressor-motor apparatus of this invention is capable of operating atrelatively high speeds, it does not necessarily have to be operated atsuch speeds and can be operated at slower speeds which are moreconventional for reciprocating type mapression-expansion chambers at theopposite ends.

of the compressor-motor apparatus counteract, which likewise minimizesvibration. In Figs. 1 and 1A, the power shaft 53 is show as comprised inan electric motor-generator II3 which is provided with suitableelectrical conducting lines Ill and II5 leading to the exterior of thecasing 54. When the device is being used as a compressor, themotor-generator II3 acts as a .motor, and, by supplying power to thepower shaft 53, imparts reciprocatory and rotary motion to the rod 38and to the pistons carried thereby for the compression of a gaseousmaterial. when the device is used as a motor, gaseousmaterial chinery.The fact that the compressor-motor apparatus of this invention operateswith high efllciency at speeds of the order 1700 to 3600 R. P. M.permits direct connection of the compressor, motor apparatus of thisinvention to standard units such as electric motors that operate at suchspeeds, whereas conventional devices operate through belting or gearingwith the exception of diaphragm type compressors which have very limitedcapacity (not over.about two cubic feet per minute) and aredisadvantageous for other reasons which have been mentioned hereinabove.

In a single stage of'the compression, it is usually not desirable toattempt to change the pressure of the gaseous material handled by theapparatus more than about four times if good emciency is to bemaintained. Where a greater ratio of compression or expansionis desired,then the compression or expansion can take place in a plurality ofstages. Thus, in two-stage compression, for example, using the device ofthis invention, one can readily maintain an exhaust pressure of 225pounds per square inch usingtwostage compression from atmosphericpressure.

In Fig, 22, a typical installation is shown' utilizingcompressormotor,apparatus embodying this invention. The device, asshown, is adapted for use as a compressor in the compressing of air towhich a. certain amount of water vapor is to be added. The air is takenin from the atmosphere at the filter inlet H6 which is provided with anatomizer I I1 that causes droplets of water to be entrained in theincoming air. The air stream is divided and flows through lines H8, H9to the inlet ports which may, for example, be the inlet ports 5| 0! themechanism shown in Fig. 1. The air is compressed in the apparatus andflows from the apparatus through lines I20,

I2I which are connected to the outlet ports 52. During compression, thedroplets of water entrained in the incoming air will tend to becomepressed air plus vapor that is discharged under elevated pressure issubstantially greater than would be the case it dry air only were beingcompressed. If only one stage of compression is desired, the smallauxiliary piston 61 at the end of the rod 38 may be dispensed with, orcut oil by closing valve I25, and the compressed air and vapor directedfor flowing out through line I22, the valve I23 being open. Asaforesaid, it I is preferable to simultaneously operate in complementaryrelation compressor apparatus according to this'invention whichcomprises two essentially similar and complementarily-acting unitslocated in axially aligned position at opposite ends of a power shaft ofa power supply unit or the like. In Fig. 22, the inlet and exhaust linesof such complementary compressor unit are shown, the referencecharacters H6, H1, H8, H9, I20, I2I, and I23 having the samesignificance as the reference characters H6, II1,-4,I8, H9, I20, I2I andI23 respectively. When the device is arranged in this manner, thegaseous material compressed by the two complementarily-disposed unitswill flow into the line I22 and be directed to a common discharge lineI24.

When it is desired to maintain the trap 60 under pressure, the dischargeline I20 may be connected thereto by line I58, the valves I51 and I55being open and the valve I58 being closed as mentioned above inconnection with the description of Fig. 1.

When multi-stage compression is desired using the device. shown in Fig.22, valve I23 may be closed and the valves I25 and I26 opened. The valveI25 is in the line I21 which is divided so as to have two portions I28and I29 which lead to the intake ports 12 of the device shown in Fig. 1.The valve I26 is in line I30 which has arms I3I and I32. that areconnected to the exhaust ports 13 of the device shown in Fig. 1.Corresponding 16 valves and connecting lines I25. I26, I21, I28, I29,I30, I3I, and I32 may be located at the opposite end of thecompressor-motor apparatus.

A device such as that shown in Fig. 22 may, for example, be used tosupply air under pressure and containing vapor to a combustion chamberof an engine where it is united with combustible material and subjectedto combustion. By increasing the pressure and/or volume of :thecompressed gaseous material, it is possible to recover the power bydirecting the combustion gases through an expansion engine. The device01 this invention is admirably suited as an expansion engine. Thus,referring to Fig. 22, the hot combustion gases can be introduced throughthe line I24 (line I24 in such case being the inlet when the device isused as a motor, instead of being an outlet when the device is used as acompressor). The hot combustion gases can be permitted to expand in onestage or two stages using the connections that have been describedhereinabove', causing the rod 38 to reciprocate and r0- tate, therotation of the rod 38 being transferred to the power shaft 53 fordriving an electric generator or any other mechanism that is to besupplied with power.

It is anadvantage of the device of this invention that it is capable ofhandling the hot combustion gases without the necessity for a lubricantin the compression-expansion chambers of the device. As has beenmentioned above,

handling hot combustion gases has heretofore presented great diflicultydue to the fact that no lubricant is known which is capable of standingup under the extremely high temperatures at which hot combustion gasesare supplied for expansion in an expansion engine.

In Fig. 23, another typical installation is shown of compressor-motorapparatus embodying this invention. In the installation shown, theapparatus is used as a compressor in a system which is maintained atsuper-atmospheric pressure and in which a supply of compressed air isfurnished for operating an expansion motor. Compressors for supplyingcompressed air are extensively used in aircraft operation for theactuation of various instruments, the system as a whole being operatedat super-atmospheric pressure. Super-atmospheric pressure is maintainedin order to avoid non-uniform actuation of the instruments resultingfrom differences in atmospheric air pressure at different altitudes. InFig. 23, a compressor of the type shown in Figs. 1 and 1A may, forexample, be employed in such a system. The air under pressure that isdischarged from the compressor is directed through lines I33 and I34 tothe high pressure line I35. An instrument to be I operated is indicatedschematically by the referorder to compensate for leakages from theclosed system, the smaller or auxiliary piston may be used to feed adesired amount of additional compressed air into the system. The air istaken into the auxiliary piston by the lines I40 and I which lead to theinlet ports 12 of the compression chamber of the auxiliary piston. Theexhaust ports 13 of the compression chamber of the auxentrainedlubricant.

17 iliary piston are connected to lines I42 and I43, the latter linefeeding into the line I39 which is on the low pressure side of the maincompression-expansion chamber of th apparatus. In order to preventexcessive pressure from building up within the system, the instrument I36 may be provided with a, relief valve I59 whichpermits escape ofgaseous material above a predetermined constant pressure to bemaintained.

When the compressor-motor apparatus is made so that the compressorportions thereof are duplicated on opposite ends of the central powershaft, the two units may, if desired, b arranged in :parallel. The linesof the second unit have been indicated by the reference characters I33,I34, I38, I39, I40, I4I', I42 and I43. When both compressor portions ofthe apparatus are operated in parallel, the valves I44 and I50 are inopen position with the valve I45 in the line I46 in closed position.Under such conditions of operation, the valve I41 .in 'line I48 is alsoclosed and the valve I49 in line I42 is open. If desired, the compressorportions of the apparatus may be operated in series, thereby operatingthe instrument I36 at a greater pressure differential than is the casewhen the compressor portions of the apparatus are operated in parallel.This can readily be accomplished by closing the valves I 44, I49 and I50and opening the valves I45 and MT. In such case, the air discharged fromexhaust lines I33 and I34 is taken to intak lines I38 and I39 forfurther compression, and the exhaust from the second compression stageand under increased pressure is taken through exhaust lines I33 and I34and thence to the instrument I36. All of the supplemental air that isfed into the system is'taken to line I39 by the line I42 and by thelines I42 and I48,'namely, to the low pressure side of the compressorwhich effects the first stage of compression.

The use of a compressor embodying this invention is especially desirablein connection with an installation such as that shown in Fig. 23. It isimportant in supplying compressed air for operating the instruments ofan airplane, for example, that the air be essentially free from anyIflubricant is carried in the, air supplied to the instrument, it tendsto become condensed on the instrument panels and in the instrumentmachinery, so that frequent cleaning is necessary. When a compressoraccording to this invention is used, it is possible to compress air andsupply it to an instrument without causing the air to come in contactwith any working parts of the apparatus on which lubricant is used.Compressor-motor apparatus embodying this invention is also desirable asthe supply of compressed air for the instruments of airplanes, since theapparatus is compact and light in weight and has a high capacity for itssize and weight. It has been general practice heretofore to operateinstruments on airplanes using a compressor of the sliding vane type,but such types of compressor have the disadvantage of requiringlubricant in the compression space'and in contact with air beingcompressed, for without lubricant such compressors operate withexcessive friction and resultant low efliciency, excessive wear andaccomplish only very limited degree of practical pressure increase.While compressors of the flexible diaphragm type may be used with-' outlubricant in the compression space, it is necessary to use conventionalvalve mechanisms which do not operate efficiently due to the rapidity ofthe pulsations of the diaphragm and frequently greatly affected byvariations in the discharge pressure that is maintained.

It is apparent from the foregoing that the compressor-motor apparatus isadvantageous for a wide variety of uses and purposes and is of specialand peculiar advantage under special conditions of operation under whichother types of compressors are either inoperable or much less desirable.While proposals have been made heretofore for providing machinerywherein a piston not only reciprocates but also has at least some rotarymotion, such prior proposals have had such serious disadvantages thatcommercial production, if carried out at all, has been extremelylimited. According to the present invention, the features andcombinations described hereinabove and recited in the appended claimsresult in decided improvements upon prior compressor-motor apparatus andhave proven of great practical advantage and utility when tested undervarying conditions including the exacting and special conditionsmentioned hereinabove.

While the compressor-motor apparatus of this invention has beendescribed in connection with certain typical embodiments thereof, it isapparent that this has been done merely for the purpose of illustrationand that the construction may be considerably varied without departingfrom the scope of this invention. Thus, while the apparatus abovedescribed affords two intake and exhaust strokes of the piston for eachrevolution of the rod to which the piston is affixed, it is apparentthat the reciprocating means can be varied to provide other numbers ofintake and exhaust strokes of the piston for each revolution of the rod.Moreover, other modifications in the compressor-motor apparatus may bemade without departing from the scope of this invention as defined inthe following claims.

I claim:

1. In a compressor-motor of the character de- I axial alignment of saidrod and to afford longitudinal and rotational movement of said rod, arotatably mounted power shaft in axial alignment with said rod, powertransfer means between said shaft and said rod adapted to aifordsimultaneously continuous rotary motion of said shaft and reciprocatoryand continuous rotary motion of said rod, a peripherally cylindricalpiston fixed to said rod in coaxial relation thereto, a cylindersurrounding said piston and coaxial therewith and arranged forreciprocation of said piston therein, the peripheral wall of said pistonbeing in close proximity to the inner wall of said cylinder andmaintained out of pressure-contact therewith'by said bearing means forsaid rod,

. chamber means which includes surface of said means, an outlet for saidchamber means, inlet valve means for controlling said inlet, and outletvalve means for controlling said outlet, said inlet and outlet and saidinlet valve means and said outlet valve means being arranged tosuccessively direct ingress of gaseous material into said chamber meansand egress of gaseous material from said chamber means during the intakeand discharge strokes respectively of said piston in said cylinder.

2. In a compressor-motor of the character described, the combinationcomprising a rod, fixed bearing means arranged to fixedly maintain theaxial alignment of said rod and to afford longitudinal and rotationalmovement of said rod, cam means interposed between said rod and a fixedmember for reciprocating said rod upon continuous rotationof said rod,said cam means com-- prising a continuous undulatory cam track and aplurality of cam guides disposed for axially balanced cam action on saidcam track relative to,

contact therewith by said bearing means for said rod, chamber meanswhich includes surface of said piston and inner wall surface of saidcylinder and the capacity of which is variable upon reciprocation ofsaid piston, an inlet for said chamber means, an outlet'for said chambermeans, inlet valve means for controlling said inlet, and outlet valvemeans for controlling said outlet, said inlet and outlet and saidinlet'valve means and said'outlet valvemeans being arranged tosuccessively direct ingress of gaseous material into said chamber meansand egress of gaseous material from said chamber means during the intakeand exhaust strokes respectively of said piston in said cylinder.

3. In a compressor-motor of the character described, the combinationcomprising a rod, bearing means affording longitudinal and rotationalmovement of said rod in a fixed axial position,

an undulatory cam ring secured to said rod in coaxial relation with theaxis of said rod and v presenting complementarycam tracks on each sideof said cam ring, a plurality of pairs of cam rollers which are fixedlypositioned with one cam roller of each pair of cam rollers opposed tothe other roller of the pair for contact with the complementary camtracks presented by said cam ring and which are disposed for axiallybalanced action on said cam ring during reciprocation and rotation ofsaid cam ring and rod, a rotatably mounted power shaft in axialalignment with saidrod, power transfer means between said shaft and saidrod adapted to afford simultaneously continuous rotary motion of saidshaft and continuous rotary motion of said rod during the reciprocationof said rod, a peripherally cylindrical piston fixed to said rod incoaxial relation thereto and spaced from said cam ring with a bearingmember of saidbearin'g means therebetween, a cylinder surrounding saidpiston and coaxial therewith arranged for reciprocation of said pistontherein, chamber means which includes surface of said piston and innerwall surface of said cylinder and the capacity of which is variable uponreciprocation of said piston, an

inlet for said chamber means, an outlet forsaid chamber means, inletvalve means for controlling said inlet, and outlet valve means forcontrolling said outlet, said inlet and outlet and said inlet valvemeans and said outlet valve means being arranged to successively directingress of gaseous material into said chamber means and egress ofgaseous material from said chamber means during the'intake and dischargestrokes respectively of said piston in said'cylinder.

4. In a compressor-motor of the character described, the combinationcomprising a rotatably mounted rod, cam means interposed between saidrod and a fixed member for -reciprocating said rod upon continuousrotation of said rod, said cam means comprising a continuousundulato'rycam track and a plurality of cam guides disposed for axially. balancedcam action on said cam track relative to the axis of said rod, aperipherally cylindrical piston coaxially fixed to said rod, a cylindersurrounding said piston in coaxial relation therewith and arranged forreciprocation of said piston therein, a cylinder head for said piston, apair of diametrically opposed inlet ports in the wall of said cylinder,a. pair of diametrically opposed outlet ports in the wall of saidcylinder angularly disposed relative to said inlet ports, and a pair ofdiametrically opposed valve ports in the side wall 01' said piston, saidinlet ports and said outlet ports and said valve ports being arrangedfor successive traversing of said inlet ports and said outlet ports bysaid valve ports upon the intake and discharge strokes respectively ofsaid piston.

5. In a compressor-motor of the character described, the combinationcomprising a rod, fixed bearing means arranged to fixedly maintain theaxial alignment of said rod and to afford longitudinal and rotationalmovement of said rod, a

cam member secured to said rod and presenting undulatory annular camtrack means coaxial with the axis of said rod, fixed cam guide meansarranged for coaction with said cam track means to effect reciprocationof said cam member and said rod upon rotation of said rod, a rotatablepower shaft in axial alignment with said rod, means for rotating saidpower shaft, an axially slidable connection between said power shaft andsaid rod adapted to rotate said rod upon rotation of said power shaft,common housing means for said cam member, for said cam guide means, andfor said axially slidable connection, a peripherally cylindrical pistonfixed to said rod in coaxial relation thereto and outside of saidhousing means and spaced from said cam member. with-a bearing member ofsaid bearing means that-is integral with said housing meanstherebetween, a cylinder surrounding said piston and coaxial therewithand arranged for reciprocation of said piston therein, the peripheralwall of said piston being in close proximity to the inner wall of saidcylinder and maintained out of pressure-contact therewith by saidbearing means for said rod, chamber means which includes surface of saidpiston and inner wall surface of said cylinder and the capacity of whichis variable upon reciprocation of said piston, an inlet for said chambermeans, an outlet for said chamber means, inlet valve means forcontrolling said inlet, and outlet valve meansfor controlling saidoutlet, said inlet and outlet and said inlet valve means and said outletvalve means being arranged to successively direct ingress of gaseousmaterial into said chamber means and egress of gaseous material fromsaid chamber means during the intake and discharge strokes respectivelyof said piston in said cylinder. 1 l

6. In a compressor-motor of the character described, the combinationcomprising a rod, fixed bearing means arranged to fixedly maintain theaxial alignment of said rod and to afford longitudinal and rotationalmovement of said rod, a

rotatably mounted power shaft in axial alignment with said rod, atelescopically slidable connection between said power shaft and said rodfor transfer of rotational power, a, cam member fixed to said rodpresenting continuous undulatory cam track means, a plurality of fixedcam guide means disposed for coaction with said cam track means toreciprocate said rod upon rotation of said rod and arranged for axiallybalanced action on said cam track means relative to the axis of saidrod, a piston fixed to said rod and spaced from said cam member with abearing of said bearing means therebetween, said piston being providedwith a peripherally cylindrical open ended skirt coaxial with the axisof said rod, 9. cylinder surrounding said piston skirt and arranged forreciprocationof said piston therein, a cylinder head for said cylinderprovided with a, reentrant m'ember adapted'to fit within the open endedskirt of said piston, a pair-of diametrically opposed inlet ports in theside wall of said cylinder, a pair of diametrically opposed outlet portsin the side wall of said cylinder, and a pair of diametrically opposedvalve ports in the skirt of said piston, said inlet and outlet ports andsaid valve ports being arranged for successive traversing of said inletports and said outlet ports by said valve ports upon reciprocatoryandrotational movement of said piston as controlled by said cammember.

7. In apparatus of the character described, the combination according toclaim 6 wherein the skirt of said piston is maintained by-said bearingmeans out of pressure-contact with the wall -of said cylinder and whichincludes means between said cam member and saidv piston for preventingpassage of lubricant toward said-piston from said cam member.

' 8. In a compressor-motor of the character described, the combinationcomprising a rod, 2. motor-generator having a rotatable power shaft,power transfer means between said power shaft and said rod adapted toeffect simultaneously continuous rotation of said power shaft andreciprocating'an'd continuous rotation of said rod,.

chamber, bearing means between said piston and, said power transfermeans aflording reciprocaii,

tory and rotational movement of said rod, and an 1 essentially gas-proofcasing about said motor-v generator and about said power transfer meansand arranged to build up pressure of gaseous material within said casingupon seepage of gaseous material from the region of saidcompression-expansion chamber past said bearing ,member toward saidpower-transfer means.

9. In a compressor-motor of the character described, the combinationcomprising; a rod, fixed bearing means arranged to fixedly maintain theaxial alignment of said rod and to afford longitudinal and rotationalmovement of said rod, a cam member secured to said rod and presentingundulatory camtrack mean coaxialwith the axis said rod adapted to rotatesaid rod upon rotation v of said power shaft, a peripherallycylindrical: piston-coaxially fixed to said'rod in spaced relation to.said cam member with a bearing member of said bearing meanstherebetween, a cylinder surrounding said piston and coaxial therewithand arranged for reciprocation of-said piston. therein,-. the peripheralwall of said piston being" in close proximity to the inner wall of saidcylinder and maintained out of pressure-contact therewith by saidbearing means for said rod, chamber means which includes surface of saidpiston and inner wall surface of said cylinder and the capacity of whichis variable upon reciprocation of said piston, an inlet for said chambermeans, an outlet for said chamber means, inlet valve means forcontrolling said inlet, and outlet valve means for controlling saidoutlet, said inlet and outlet and said inlet valve means and said outletvalve means being arranged to successively direct ingress of gaseousmaterial into said chamber means and egress of gaseous material fromsaid chamber means during the intake and discharge strokes respectivelyof said piston in said cylinder and said compressor-motor apparatuscomprising an essentially gas-proof casing which is disposed about saidcam-member, said cam guide means, said electrical motor-generator andsaid axially slidable connection and which is arranged to builduppressure within said casing uponseepage of gaseous material past saidhearing member in the direction from said piston toward, saidcam-member.

10. Infa compressor-motor of the character described, the combinationcomprising a rod, a peripherally cylindrical piston fixed to said rod incoaxial relation thereto, reciprocating means spaced from said pistonfor axially reciprocating said rod during rotation of said rod, spacedbearings between said piston and said reciprocating means adapted tofixedly maintain. the axial alignment of said rod and to affordlongitudinal and rotational movement of said rod, trap means betweensaid spaced bearings adapted to retain any lubricant passing the bearingof said spaced bearings that is more adjacent said reciprocating meansbefore it reaches the bearing of said spaced bearings that is moreadjacent variable upon reciprocationof said piston, an

inlet for said chamber means, an outlet for said chamber means, inletvalve means for controlling said inlet, and outlet valve means forcontrolling said outlet, said inlet and outlet and said inlet valvemeans and said outlet valve means being arranged to successively directingress of gaseous material into said chamber means and egress ofgaseous material from said chamber means during the intake and dischargestrokes respectively of said piston in said cylinder.

ment of said rod and to afford longitudinal and rotational movement ofsaid rod, a housing surrounding said reciprocating means, a supportmember which projects away from said piston inwardly into said housing asubstantial distance and in which said bearing member is secured, acylinder surrounding said piston and coaxial therewith and arranged forreciprocation of said piston therein, the peripheral wall of said pistonbeing in close proximity to the inner wall of said cylinder andmaintained out of pressure-contact therewith by said bearing means forsaid rod,

of said cylinder are of substantially lesser angular extent about theaxis of said rod than said inlet ports.

16. In a compressor-motor of the character described, the combinationaccording to claim 14 wherein said inlet and outlet ports in the wall ofsaid cylinder are simple openings and wherein the valve ports in theside wall of said piston likewise are simple openings.

17. In a compressor-motor of the character described, the combinationcomprising a rotatably mounted rod, a peripherally cylindrical pistonaffixed coaxially to said rod; means for reciprocating said rod uponcontinuous rotation of said rod, a cylinder surrounding said piston andarranged for reciprocation of said piston therein, a cylinder head forsaid cylinder on each end of said piston, a first pair of diametricallyopposed valve ports in the side wall of said piston communicating withone end of said piston, a second pair of diametrically opposed valveports in the chamber means which includes surface of said piston andinner wall surface of said cylinder and the capacity of which isvariable upon reciprocation of said piston, an inlet' for said chambermeans, an outlet for said chamber means, inlet valve means forcontrolling said inlet, and outlet valve means for controlling saidoutlet, said inlet and outlet and said inlet valve means and said outletvalve means being arranged to successively direct ingress of gaseousmaterial into said chamber means and egress of gaseous material fromsaid chamber means during the intake and discharge strokes respectivelyof said piston in said cylinder.

13. In a compressor-motor of the character described, the combinationaccording to claim 12 which comprises trap means between said bearingmember and said piston, and a second hear-- ing member between said trapmeans and said piston, said second bearing member being carried by asupport which projects away from said piston inwardly into said trapmeans a substantial distance.

14. In a compressor-motor of the character described, the combinationcomprising a rotatably mounted rod, a peripherally cylindrical pistonfixed coaxially to said rod, means for reciprocating said rod uponrotation of said rod, a cylinder surrounding said piston and arrangedfor-reciprocation of said piston therein, a cylinder head for saidcylinder, a pair of diametrically opposed inlet ports in the wall ofsaid cylinder, a pair of diametrically opposed outlet ports in the wallof said cylinder angularly disposed with respect to said inlet ports,and a pair of diametrically opposed valve ports in the peripherallycylindrical side wall of said piston, said inlet and outlet ports in thewall of said cylinder and said valve ports in the side wall of saidpiston being arranged for successive traversing of said inlet ports andsaid outlet ports by said valve ports upon intake and discharge strokesrespectively or said piston, and said inlet ports being of substantiallygreater angular extent about the axis of said rod than said valve portsin the side wall of said piston.

15. In compressor-motor apparatus of the character described, thecombination according to claim 14 wherein said outlet ports in the Wallside wall of said piston disposed angularly with respect to said firstpair of valve ports and communicating with the other end of said piston,a pair of diametrically opposed inlet ports in the wall of saidcylinder, a pair of diametrically opposed outlet ports in the wall ofsaid cylinder, said inlet and outlet ports being common to said firstand second valve ports and being arranged to be successively andalternately traversed by said first and second pairs of valve ports uponreciprocation and continuous rotation of said piston.

18. In a compressor-motor of the character described, the combinationcomprising a rod, a piston fixed to said rod, said piston comprising apair .of peripherally cylindrical, oppositely extending open endedskirts coaxial with the axis of said rod with a separator walltherebetween, means for controlling simultaneous reciprocatory androtary movement to said rod and said piston axially of said rod, acylinder surrounding said skirts and coaxial therewith and arranged forreciprocation of said piston therein, a reentrant cylinder head for eachof said piston skirts and arranged to fit therein, a first pair ofdiametrically opposed valve ports extending directly through one of saidpiston skirts, a second pair of diametrically opposed valve portsextending directly through the other skirt of said piston and angularlydisposed with respect to said first valve ports, a pair of diametricallyopposed intake ports extending directly through the wall of saidcylinder, a, pair of diametrically opposed outlet ports extendingdirectlythrough the wall of said cylinder, said inlet and outlet portsbeing common to said first and second valve ports and being arranged tobe successively and alternately traversed by said first and second pairsof port valves upon the intake and discharge strokes of said pistonskirts on each side of said barrier.

19. In a compressor-motor of the character described, the combinationaccording to claim 18 ,wherein said barrier between said oppositelyextending piston skirts is provided with a hub of substantially greaterextent along the axis of said rod than the thickness of said barrier,said hub surrounding and being rigidly secured to said rod.

20. In a compressor-motor of the character described, the combinationcomprising a rotatably mounted rod, 2. peripherally cylindrical pistonaflixed to said rod, means for reciprocating said rod upon continuousrotation of said rod, a cylinder surrounding said piston and arrangedfor reciprocation of said piston therein, a cylinder head for saidcylinder on each end 01' said piston 01' said piston opening directlyinto the chamber on one side of said piston, a second valve port in theend wall of said piston angularly disposed with respect to said firstvalve port and opening directly into the chamber on the other end ofsaid piston, an inlet port in the side wall of said cylinder, and anoutlet port in the side wall of said cylinder angularly disposed withrespect to said inlet port, said inlet and outlet ports being common tosaid first and second valve ports and arranged to be successively andalternately upon reciprocation and continuous rotation of said piston.

21. In a compressor-motor of the character described, the combinationcomprising a rotatably mounted rod, cam means for reciprocating said rodupon rotation of said rod, a peripherally cylindrical piston coaxiallyfixed to-said rod, a cylinder surrounding said piston and arranged forreciprocation or said piston therein, a cylinder head (or said cylinder,an inlet port and an outlet port in the wall of said cylinder, a portvalve in the side wall of said piston, said inlet and outlet ports insaid cylinder and said port valve in the side wall of said piston beingarranged for successive traversing of said inlet and outlet ports bysaid valve port upon intake and discharge strokes respectively ofsaidpiston, and means for changing therelative angularposition about theaxis of said rod between said cylinder and said cam means so as toreverse the action of said compressor-motor.

22. In a compressor-motor of the character d scribed, the combinationcomprising a rotatably mounted rod, cam means for imparting axiallyreciprocatory movement to said rod upon rotation of said rod, a pistonfixed .to said rod, said piston including a peripherally cylindricalopenended skirt coaxial with the axis of said rod, a cylindersurrounding said skirt and coaxial there. with and arranged forreciprocation of said piston therein, cylinder head means for saidcylinder, inlet and outlet ports in said cylinder, port valve means insaid skirt of said piston, said inlet and outlet ports in said cylinderand said port valve means in said skirt being arranged for successivetraversing of said inlet and outlet ports by said valve ports uponintake and discharge strokes respectively of said piston, and means forchanging the angular position of said cylinder relative to the axis orsaid rod so as to reverse the action of said compressor-motor.

23. In a compressor-motor'oi the character described, the combinationcomprising a rotatably mounted rod, means for imparting axiallyreciprocatory movement to said rod simultaneously with rotation of saidrod, a first peripherally cylindrical piston fixed to said rod incoaxial relation therewith, first chamber means including a first fixedcylinder for reciprocation of said first piston therein and includinginlet and outletv ports and valve means for controlling said ports andarranged for successive introduction oi! gaseous material into saidchamber means during the intake stroke of said first piston and forexpulsion of gaseous material from said chamber means during thedischarge stroke of said first piston, a second peripherally cylindricalpiston fixed to said rod in coaxial relation to said rod traversed bysaid first and second valve ports and in spaced relation to said firstpiston, second chamber means including a second cylinder forreciprocation of said second piston therein and including inlet andoutlet ports and valve means for controlling said ports and arranged forsuccessive introduction oi gaseous material into said second chambermeans during the intake stroke of said second piston and for expulsionofgaseous material from said chamber means during the discharge stroke oisaid second piston,

and means for directing gaseous material from the discharge port of saidsecond chamber means to the intake port of said first chamber means.

24. In a compressor-motor or the character described, the combinationcomprising a first rod, means 'for fixedly maintaining the axial alignmerit of said rod, a second rod, means for fixedly maintaining the axialalignment of said second rod in axial alignment with said first rod,means between the opposed ends of said first and second rods foreffecting rotation of said rods at the same speed of rotation, means foraxially reciprocating said first rod uponrotation 01' said first rod,means for axially reciprocating said second rod upon rotation of'saidsecond'rod in complernentary and opposite relation to the reciprocationof said first rod, a first peripherally cylindrical piston fixed to saidfirst rod in axial relation thereto, first chamber means including afixed cylinder for reciprocation of said first piston therein includinginlet and outlet ports and'valve means for controlling said ports andarranged for successive introduction and expulsicgr of gaseous materialinto and from said first chamber means during the intake and dischargestrokes respectively of said first piston, second chamber means.

including a fixed cylinder for reciprocationpt said second pistontherein including inlet and outlet ports and valve means for controllingsaid ports and arranged for successive introduction and expulsion ofgaseous material into and from said second chamber means during theintakeaxially reciprocating said rod upon continuous rotation of saidrod, said cam means comprising continuous undulatory cam track means andcam guide means for cooperation with said continuous undulatory camtrack means, a rotatably mounted power shaft in axial alignment withsaid rod, .an axially slidable connection between said power shaft andsaid rod adapted to rotate said rod upon rotation of said power shaft, aperipherally cylindrical piston affixed to said rod in coaxial relationthereto and spaced from said cam means with a bearing comprised by saidbearing means therebetween, a cylinder surrounding said piston andarranged for reciprocation of said piston therein, the peripheralsurface of said piston being maintained out of pressure-contact with theinner wall of said cylinder, a cylinder head for said cylinder, inletand outlet port-s in the side wall of said" cylinder, and valve portmeans in the side wall of said piston, said inlet and outlet ports andsaid valve port means being arranged for controlling ingress andexpulsion of gaseous ma.-

terial from said cylinder upon the rotation'and

